Kakoune detect indent

detect-indent.kak

set-option global tabstop 4
set-option global indentwidth 4

declare-option -hidden str detect_indent_script %sh{ echo "${kak_source%/*}/index.js" }

define-command detect-indent %{
    evaluate-commands %sh{
        node "$kak_opt_detect_indent_script" "$kak_buffile"
    }
}
hook global BufCreate .+ detect-indent

index.js

const fs = require('fs')
const detectIndent = require('detect-indent')
console.error(process.argv) // debugging, won't be taken by kakoune

const file = fs.readFileSync(process.argv[2], 'utf8')
const indent = detectIndent(file).indent

let spaces = 0
if (indent[0] === ' ') {
	spaces = indent.length
}

if (spaces) {
	console.error(spaces + ' spaces!')
	console.log(`
		set-option buffer tabstop ${spaces}
		set-option buffer indentwidth ${spaces}
		set-option buffer aligntab false
		hook buffer InsertChar '\t' %{ execute-keys -draft "h${spaces}@" }
	`)
} else {
	console.error('tabs!')
	console.log(`
		set-option buffer indentwidth 0
		set-option buffer aligntab true
	`)
}